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Bill McAllister from Irving Farm talks Espresso

The definition of espresso is a method of brewing coffee according to the Specialty Coffee Association of America, a trade group that represents and undoubtedly has some direct connection to every person and place in this book. Yet the difference between a coffee made using a Chemex versus a vacuum pot or any other coffee maker is negligible compared to what an espresso machine produces. The root cause is pressure. Espresso machines take water that would normally be poured or sprinkled onto coffee and forces it through the pressure of the atmosphere. But who came up with that? How did they know it could make coffee so much more delicious than normal?

The etymology of espresso reveals a lot about the intention of this technology. If we Anglicize the word into “expresso”, it is easy to see that the drink needs to be made quickly, but also that it needs to be made expressly for a consumer. Back in Italian, it’s just as easily interpreted as “to press out”, bringing pressure back into the picture. Put it all together, and you have a device that makes coffee quickly, one at a time, using pressure. All of this is according to Andrea Illy (yes, that Illy) as written in Espresso Coffee, one of the few textbooks on coffee.

It paints a somewhat primitive picture of Italy in the 1880s, where the first patents for espresso machines are traced. The technology at the time was coarse and rugged. It relied on huge boilers heated by fire that used a head of steam to push water through the ground coffee. A barista would be hard-pressed to make anything that wasn’t quite bitter. This was espresso for decades. But then, manufacturers introduced a lever and piston as an alternative method of generating pressure. This change allowed the machines to be much smaller, brew at pressures that have become today’s standard, and use water that isn’t super-heated. All of a sudden espresso carts became a reality, bringing the means of caffeination to even more people. But the most important part of the change in the machines is that it is no longer impossible for a shot to be pulled that is more than something used as a dose of energy.

The espresso of today and its potential to be mind-blowingly delicious has a culture surrounding it that elevates it above the rest of coffee. Cafes have moved far beyond just dishing out shots to give workers a boost mid-afternoon. A coffee shop that wants to be the talk of the town these days draws customers in by talking about the specific farms their coffee is from, the agronomy of the plant from which the coffee is harvested, and a level of precision that requires scales that wouldn’t be out of place in a display on St Mark’s Place.

How we went from pre-industrial caffeine machines relying on levers and pistons to today’s models doesn’t contain any big eureka moments, but is mostly a steady stream of smart revisions. Baristas realized early on that their ability to reliably make the most delicious espresso they’ve tasted required having a machine they could count on to work the same way every time. To this end, springs and levers were replaced by electric pumps and gas burners were replaced by heating elements controlled by computers. Yet with all of these, advances were driven by the trial and error of passionate baristas, because despite the long history of espresso, there is not a lot of scientific writing about the process with which it is made. When a handful of videos featuring clear plastic portafilters started trickling out in the last few years, coffee pros everywhere were astounded—the first real evidence in over a century as to what’s happening when making espresso!

Explanations of how and why espresso works may be lacking, but we can still gather a few lessons as consumers. A properly prepared shot looks elegant as it pours into a cup, flowing thick but steady, like warm honey, a promise of flavor that delivers on the intoxicating smell characteristic of coffee shops everywhere. At its best, a coffee brewed as espresso sees its flavors held under a magnifying glass. The experience is intense, but often divisive: fruity Ethiopian coffees taste like someone plopped jam in the bottom of your demitasse, so lush with fruit flavor and sweetness it seems impossible that the only ingredient is coffee. The second you sip a good espresso, all thoughts of history are fleeting memories; you thoughts are now on the delicious beverage in your hands.